[Corsa C 2000-2006] Wont start. ECU shows 600rpm

[andy]

My Corsa c 1.0 2001 wont start RAC have looked and found the ECU is showing 600rpm with just the ignition on. Compression fine, fuel fine. He thought The ECU could be spiked as it had been jump started. Before I replace the ECU is there anything else that would cause this. The battery has been disconnected for weeks no fault codes stored.

[Alanco]

HI Andy and welcome.

mate i'm just throwing ideas up in the air but has it got a flywheel sensor of some sort - thinking engine is spining whjen it aint ??? - breaker job

good luck

[Rocksta]

I'd say it's probably the crank sensor. Sounds like it's reading wrong to me.
Rac aren't the best people to diagnose faults to be honest.
Bit more information would be nice though.

[andy]

I'd say it's probably the crank sensor. Sounds like it's reading wrong to me.
Rac aren't the best people to diagnose faults to be honest.
Bit more information would be nice though.

[andy]

[andy]

Thanks for the thoughts. The history is the timing chaintiming chain, took the head off and checked that the valves weren't bent. All seemed ok. However during this time I jump started it and the RAC guy thought that I might have spiked the ECU. He checked compression - fine. Fuel - fine. But got two different reading with his analyser one 75rpm and the other 600rpm. both with just the ignition on. I had removed the crankshaft speed sensor and check the resistance previously it came out at 700ohms. so I thought that was ok. It is possible I didn't put it back correctly or that it wasn't working properly. He got no reading from it when the engine was turned over so thought that the ECU was dodgy. From what you say it might be worth changing the sensor and checking the connection. Would the ECU be Kaput from one dodgy jump start?

[andy]

Well the crank shaft sensor is changed. waiting for the battery to charge now. then we will see if its fixed.

[andy]

Well the crank shaft sensor is changed. waiting for the battery to charge now. then we will see if its fixed.

Battery is charged and still it wont start! not sure where to go now.

[Brink]

You can try swapping an ecu from a similar car to check.

trouble is your heading for parts bingo unless you get it properly diagnosed.

[Taurus]

You can fry an ECU but it's unusual for one to go as per your description. Did you cross any wires or connect anything back to front when you did the jump start? That can cause damage, but a normal jump start shouldn't do any harm.

How did you set up the timing? Did you use the timing kit to set the phase disc on the inlet camshaft? If that's out then the camshaft sensor and the crankshaft sensor will be out of sync and the varying rpm readout may be the result of the ECU trying to make sense of two conflicting inputs.

Check the ECU earth was reconnected when you took the head off - that can cause fun and games.

Also, just to double check, are the rest of the instruments (eg petrol gauge) reading properly?